My coolant has been getting low for some time now, but my bus-A/C is still working [for now]

I have tried a few places to get it topped-up, but no one will touch it until we can figure out what type of refrigerant is in it.

I have been told that if it is the old type then I must do a system up-grade. [or get it topped up in Mexico... :-) ]If it is the new type then it must be confirmed some how to avoid mixing and causing damage.

Does anyone know how one tells what kind of refrigerant is in a system... Are there test that can be done.

All service records I have and calls to the previous owner have produced no clues.

Steve, generally a sticker is attached either near the original toilet dump or inside the rear engine doors that says '134', etc. I don't know about a test for the actual freon. However, R12 (original) and R134 systems have different size fittings where you add freon. You might find someone who has R134 equipment and see if it fits the fittings. Darren

More...I got tired of paying someone to top off my MC9 bus air. I was getting charged a service fee plus $20 a pound for R134. I went to the local auto parts store and bought the manifold and guages for about $60. Then I went to SAM's warehouse club for the Freon. A 30 pound bottle was $180. It doesn't take much to learn how to read the guages.

Your MC9 system holds a lot of freon!!! When it gets too low, the clutch on your compressor will stop engaging. Then you'll have to pull a vacuum to be able to add freon at all. Catch it while you can! A good way to look for leaks is check your hoses and fittings for dirt. A leak will leave the outside of the hose or fitting kinda oily and dust will accumulate at that point.

I had my system pressure tested for leaks, something they said they had to do before they even consider adding anything.

I like your suggestion about getting the gages and topping up myself and I'll do that as soon as I can figure out for sure what type of freon I have. I was also told that all hoses had to be replaced if converting from R12 to R134. I didn't know about the different size fittings for each type, but that would make sense so as to prevent accidental mixing of the two types.

My bus never had a factory toilet [it was a 49 passenger coach] but I will check to see if there is any sticker in the engine compartment, but I don't recall seeing any.

Almost any GOOID size A/C shop will have an "A/C gas analysis unit" - a fairly expenseive unit that tell them exactly what type refrigerant is in a system or bottle - r-12 / r-134 / after market propane mix

They tested a bottle of r-12 I purchased over via ebay for free - what a deal r-12 20lbs bottle (small) full for $12 (yep $12) - it took a year to slowly transport the bottle from California to Florida - via a classic GMC club I belong to

Almost any GOOID size A/C shop will have an "A/C gas analysis unit" - a fairly expenseive unit that tell them exactly what type refrigerant is in a system or bottle - r-12 / r-134 / after market propane mix

They tested a bottle of r-12 I purchased over via ebay for free - what a deal r-12 20lbs bottle (small) full for $12 (yep $12) - it took a year to slowly transport the bottle from California to Florida - via a classic GMC club I belong to

Pete RTS/Daytona

Thanks Pete...

I was also told that R12 was prohibited and that no service shop was allowed to use it any more.... This might be a country specific thing, Not sure on the U.S. laws, Canada says no way and like always, in Mexico, you can get anything done...

Have you encounter any regulations to that effect or is the info I was given wrong...?

Steve, I'm not sure that R12 is illegal, its just more trouble to handle so shops don't like to. When working on an R12 system, the shop has to recover all the gas and not let it leak into the atmosphere. Then they have to dispose of it if not putting it back into the system. I'm certainly not advising it but some people just let it go like we did 25 years ago.

Your toilet dump would have been in the curbside engine compartment. You can sometimes get to parts of your compressor easier through this door. The R134 sticker may be there. Since you mentioned hoses, the R134 ones are different and that may be evidence of a conversion. However, I've seen the old hoses left on after conversions so that's not a sure-fire method.

the r-12 has screw on fittings, the 134 has a quick connect, all you need to do is look at it, you can fill it yourself witha kit from any auto parts, the r-12 is not illegal but has to be serviced by licenced teck and recovered (politics) you can buy the cans of 134 anywhere as well, but if you have a leak you need to fix it as it will be a pain filling it all the time, i pulled mine out of my 06 and trashed it, put in a couple of street rod units and havent had to add a thing to the system since. R-12 is very expensive and hard to get, not sure the current price , if you got that id change it over and get the leak fixed at the same time. There is nobody that will sell you r-12 unless you are licenced. i still have some around from the old days. Frank allen4106

the r-12 has screw on fittings, the 134 has a quick connect, all you need to do is look at it, you can fill it yourself witha kit from any auto parts, the r-12 is not illegal but has to be serviced by licenced teck and recovered (politics) you can buy the cans of 134 anywhere as well, but if you have a leak you need to fix it as it will be a pain filling it all the time, i pulled mine out of my 06 and trashed it, put in a couple of street rod units and havent had to add a thing to the system since. R-12 is very expensive and hard to get, not sure the current price , if you got that id change it over and get the leak fixed at the same time. There is nobody that will sell you r-12 unless you are licenced. i still have some around from the old days. Frank allen4106

Street rod units are add-on air conditioners for older cars from the 50s and 60s that have generally been restored.

See www.hotrodair.com or www.vintageair.com for some examples. I have no idea how multiples of these could be put in a bus. If I was going this route I would probably get the auxiliary air conditioning units from Welch industries designed for a bus.

Street rod units are add-on air conditioners for older cars from the 50s and 60s that have generally been restored.

See www.hotrodair.com or www.vintageair.com for some examples. I have no idea how multiples of these could be put in a bus. If I was going this route I would probably get the auxiliary air conditioning units from Welch industries designed for a bus.

My 2 cents: My MC9, a NJT serviced coach lost coolant over the winters, a little more each year until this past winter, system empty. Inspection revealed leak'n low pres. hose at compressor. Went to local hose co., ordered both low and high pres. hoses. My coach was converted to R134A before i purchased it, all new hoses and compressor. I buy refrigerant in 30#s and the price over the last couple of years have climbed quite a bit. I went with ENVIRO-SAFE (industrial) 36#. $159.00. So far so good and very cold. I have also used FREEZE-12 in other vehicles and no problems, also cost less than R134A. Forget about R12, it's available, the last i saw was about $1200.00 for 30#s.

Steve, they are after market add on a/c units that produce 22500 btu s each, i have two, they look like toys and some think they couldnt do the job, they use 13000 btu roof tops and think thats fine but my 22500 are not big enough according to some, but when we go down the road in the Texas summer and its 74 deg in the front driver seat i could care less. thats the way it works and many times we only run one. they have done a great job for us>, there are about 20 or so others out there with thesame setup, and ive heard no complaints yetFrank Allen4106